Video Communication System, Device and Method Based on Feedback Reference Frames

ABSTRACT

Embodiments of the invention provide a video communication system, device and method on the basis of feedback reference frame. The method includes: receiving, by a video encoding end, video frame information fed back by a video decoding end, determining a reference frame for encoding current video image according to the video frame information; encoding the current video image according to determined reference frame, and sending a video frame formed after the encoding; decoding, by the video decoding end, received video frame, and feeding back the video frame information to the video encoding end through a network and according to decoding result. By adopting embodiments of the invention, network data flow may be reduced. Meanwhile, phenomenon which may cause greater impact on the network, when it is necessary to send larger data amount since frame-loss or failed-decoding, may be avoided.

FIELD OF THE INVENTION

The present invention relates to video communication technologies, andmore particularly, to a video communication system, device and method onthe basis of feedback reference frame.

BACKGROUND OF THE INVENTION

With the development of video communication technologies and theimprovement of network bandwidth, more and more users adopt videocommunication, such as network video playing, video chat, videoconference and video-on-demand. Thus, life and work of societal publichave been greatly enriched. Meanwhile, further development of the videocommunication technologies and network technologies are accelerated.

However, since the instability of network bandwidth and networktransmission quality easily caused by complicated architecture and “besteffort” characteristics of the Internet, video communication quality ofcurrent video communication system is difficult to be guaranteed undersome circumstances, which has a serious influence on users' usage. Oneof primary bottlenecks affecting video communication quality currentlyis pause of video transmission caused by loss of network packets. FIG. 1is a brief data flow diagram illustrating existed video communicationtechnologies, in which video encoding end encodes video frames accordingto predefined rules and frame type, and then sends the encoded videoframes to video decoding end through a network. The video decoding enddecodes received video frames, and then plays the video.

However, according to currently widely applied technical solution, whennetwork packets are lost in network congestion caused by a certainreason and video decoding end cannot restore decodable data withremaining data, it is necessary for the video encoding end to encode anIntra frame (I frame) with large data amount to be sent to the videodecoding end, thus, not only bandwidth resources are wasted, but alsoexisted network congestion is further aggravated.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a video communicationsystem, device and method on the basis of feedback reference frame, soas to reduce data amount transmitted when frames are lost or decoding isfailed in a video communication process.

Technical schemes provided by embodiments of the invention areimplemented as follows.

A video communication method on the basis of feedback reference frame,which is applied in a system including a video encoding end and a videodecoding end, the method including:

receiving, by the video encoding end, video frame information fed backby the video decoding end, determining a reference frame for encodingcurrent video image according to the video frame information, encodingthe current video image according to determined reference frame, sendinga video frame formed after the encoding;

decoding, by the video decoding end, received video frame, and feedingback the video frame information to the video encoding end through anetwork according to decoding result.

A video communication system on the basis of feedback reference frame,in which the system includes a video encoding end, a video decoding end,a network respectively connected with the video encoding end and thevideo decoding end, the video encoding end at least includes a videocapture module adapted to capture current video image, a video encodingmodule adapted to encode the current video image, and a datatransmitting module adapted to send a video frame formed after encodingby the video encoding module to the video decoding end through thenetwork, the video decoding end at least includes a video decodingmodule adapted to decode received video frame, the video encoding endfurther includes a reference frame judging module, the video decodingend further includes a feedback module;

the reference frame judging module is adapted to receive the video frameinformation fed back by the feedback module, and determine a referenceframe for encoding the current video image according to the video frameinformation;

the video encoding module is adapted to encode the current video imageaccording to the reference frame determined by the reference framejudging module;

the feedback module, which is connected with the video decoding module,is adapted to feed back the video frame information to the videoencoding end through the network and according to decoding result of thevideo decoding module.

A video encoding communication device on the basis of feedback referenceframe, which at least includes a video capture module adapted to capturecurrent video image, a video encoding module adapted to encode thecurrent video image, and a data transmitting module adapted to transmita video frame formed after encoding by the video encoding module to avideo decoding end through a network, the device further includes:

a reference frame judging module, which is located between the videocapture module and the video encoding module, adapted to obtain videoframe information fed back by the video decoding end, determine areference frame used to encode the current video image according to thevideo frame information, and provide determined reference frame to thevideo encoding module which is adapted to execute encoding operationsfor the current video image.

A video decoding end device on the basis of feedback reference frame, inwhich the device at least includes a video decoding module adapted todecode received video frame, the device further includes:

a feedback module, which is connected with the video decoding module,adapted to feed back video frame information to a video encoding endthrough a network and according to decoding result of the video decodingmodule.

In the video communication system, device and method on the basis offeedback reference frame provided by embodiments of the invention, thefeedback module at the video decoding end feeds back video frameinformation of the video decoding end to the video encoding end, whenframes are lost or decoding is failed at the video decoding end, thevideo encoding end may utilize the video frame information fed back toencode an Inter frame (P frame) with high compression ratio and smalldata amount, and may maintain the video communication. Thus, networkdata flow may be reduced during the video communication process.Meanwhile, phenomenon which may cause greater impact on the network,when it is necessary to send larger data amount since frame-loss orfailed-decoding, may be avoided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating structure of a system aboutexisted video communication technologies.

FIG. 2 a is a diagram illustrating basic structure of a system inaccordance with an embodiment of the invention.

FIG. 2 b is a diagram illustrating detailed structure of a system inaccordance with an embodiment of the invention.

FIG. 2 c is a diagram illustrating structure of an encoding end devicein accordance with an embodiment of the invention.

FIG. 2 d is a diagram illustrating structure of a reference-framefeedback module in an encoding end device in accordance with anembodiment of the invention.

FIG. 2 e is a diagram illustrating structure of a decoding end device inaccordance with an embodiment of the invention.

FIG. 3 is a schematic diagram illustrating a brief flow in accordancewith an embodiment of the invention.

FIG. 4 is a diagram illustrating detailed flow about encodingcommunication in accordance with an embodiment of the invention.

FIG. 5 is a diagram illustrating detailed flow about decodingcommunication in accordance with an embodiment of the invention.

EMBODIMENTS OF THE INVENTION

In a video communication system on the basis of feedback reference frameprovided by embodiments of the present invention, a feedback module,which is configured to feed back video frame information of videodecoding end to video encoding end, is added in the video decoding end;a reference frame judging module, which is configured to receive thevideo frame information fed back by the feedback module, and determine areference frame used to encode current video image according to thevideo frame information, is added in the video encoding end. Thus, whenframes are lost or decoding is failed at the video decoding end,operations performed by the video encoding end in the prior art toencode an Intra frame (I frame) with large data amount once again and tosend the I frame to the video decoding end may be avoided. Detaileddescriptions will be provided in the following.

In order to make objectives, technical solutions and advantages of theinvention clearer, detailed descriptions about the invention will beprovided in the following accompanying with attached figures andspecific embodiments.

With reference to FIG. 2 a, FIG. 2 a is a diagram illustrating basicstructure of a video communication system on the basis of feedbackreference frame in accordance with a first embodiment of the invention.The system includes a video encoding end 10 a, a video decoding end 20a, and a network 30 a which is respectively connected with videoencoding end 10 a and video decoding end 20 a. Video encoding end 10 aincludes at least a video capture module 11 a configured to capturecurrent video image, a video encoding module 12 a configured to encodecurrent video image, and a data transmitting module 13 a configured totransmit a video frame to video decoding end through a network, in whichthe video frame is formed after encoding by the video encoding module.The video decoding end includes at least a video decoding module 22 a,which is configured to decode received video frames. In the embodimentof the invention, as shown in FIG. 2 a, video encoding end 10 a furtherincludes a reference frame judging module 14 a, video decoding end 20 afurther includes a feedback module 24 a.

Reference frame judging module 14 a receives video frame information fedback by feedback module 24 a, and determines a reference frame forencoding current video image according to the video frame information.

Thus, video encoding module 12 a may encode current video imageaccording to the reference frame determined by reference frame judgingmodule 14 a, to form a video frame. And then, the video frame is sent tovideo decoding end 20 a through network 30 a. The process of videoencoding module 12 a encoding current video image according to thereference frame determined by reference frame judging module 14 a may beimplemented as follows. Video encoding module 12 a encodes current videoimage with an inter-frame encoding mode to form a video frame(specifically is an Inter frame, P frame for short).

Feedback module 24 a connecting with video decoding module 22 a, isconfigured to feed back video frame information to video decoding end 10a according to decoding result of video decoding module 22 a.

It should be explained that, connection relationships among each devicein all the figures of the invention are existed for clearly clarifyinginformation interaction and control process, thus they should beunderstood as logical connection relationships, instead of limiting tophysical connections. Besides, it should be explained that, both videoencoding end 10 a and video decoding end 20 a may be client and/orserver end, or software run in client and/or server end. Meanwhile,roles of them are relative, which is not confined to a fixed role. As iswell known by persons having ordinary skill in the art, video encodingend 10 a and video decoding end 20 a include physical or logical buffer,so as to facilitate storing data necessary to be buffered, e.g., tostore captured video image, video frame information, encoded videoframe, decoded video frame, etc.

In the foregoing, descriptions about basic structure of the videocommunication system provided by an embodiment of the invention wereprovided. In the following, descriptions about detailed structureprovided by an embodiment of the invention are provided.

With reference to FIG. 2 b, FIG. 2 b is a diagram illustrating detailedstructure of a video communication system on the basis of feedbackreference frame in accordance with the first embodiment of theinvention. As shown in FIG. 2 b, the system may include a video encodingend 10 b, a video decoding end 20 b, and a network 30 b which isrespectively connected with video encoding end 10 b and video decodingend 20 b. Video encoding end 10 b includes at least a video capturemodule 11 b, a video encoding module 12 b, a data transmitting module 13b and a reference frame judging module 14 b. Video decoding end 20 b mayinclude a video decoding module 22 b and a feedback module 24 b. Videocapture module 11 b, video encoding module 12 b, data transmittingmodule 13 b, reference frame judging module 14 b, video decoding module22 b and feedback module 24 b are respectively similar to video capturemodule 11 a, video encoding module 12 a, data transmitting module 13 a,reference frame judging module 14 a, video decoding module 22 a andfeedback module 24 a in FIG. 2 a. No further descriptions will beprovided here.

Preferably, reference frame judging module 14 b judges whether videoframe information fed back by feedback module 24 b includes frame-lossinformation and video frame number information. If yes, operations fordetermining the reference frame will be executed.

When reference frame judging module 14 b judging the video frameinformation fed back by feedback module 24 b doesn't include frame-lossinformation and video frame number information, video encoding module 12b encodes current video image with a method, in which an I frame isencoded every 20 frames, and a P frame is encoded every 5 frames withthe latest I frame as the reference frame.

When judging the video frame information fed back by feedback module 24b includes the frame-loss information and video frame numberinformation, reference frame judging module 14 b continuously judgeswhether there is a video frame corresponding to the video frame numberinformation currently, if yes, takes the video frame corresponding tothe video frame number information as the reference frame.

When reference frame judging module 14 b judges there is no video framecorresponding to the video frame number information currently, videoencoding module 12 b encodes current video image in the manner of Iframe.

Preferably, decoding result includes decoding success and decodingfailure.

When decoding result of video decoding module 22 b is decoding failure,feedback module 24 b feeds back the video frame information to referenceframe judging module 14 b through the network.

Preferably, the video frame formed after encoding by video encodingmodule 12 b is sent by data transmitting module 13 b in the manner ofvideo frame data to video decoding end 20 b through network 30 b. Asshown in FIG. 2 b, video decoding end 20 b needs to include a datareceiving module 21 b connecting with video decoding module 22 b, whichis configured to receive video frame data transmitted by datatransmitting module 13 b, to package received video frame data again toform a video frame, and to send the video frame to video decoding module22 b.

In the embodiment, as shown in FIG. 2 b, video decoding end 20 b furtherincludes a video playing module 23 b connecting with video decodingmodule 22 b, which is configured to play video image decodedsuccessfully.

According to video communication technical principle, current videoimage is an original video image (may also be referred to as originalframe), which is captured by video capture module 11 b and sent to videoencoding module 12 b. The video frame is formed after encoding receivedoriginal frames according to predetermined encoding algorithm by videoencoding module 12 b, the encoding mode thereof may be I frame or Interframe (P frame for short).

The I frame refers to an encoding mode, which adopts picture compressiontechnologies and only compresses space redundant information within thevideo frame. The P frame refers to another encoding mode, which not onlycompresses space redundant information within the video frame, but alsocompresses data utilizing time redundant between the video frame and adesignated reference frame, that is, the P frame performs time-domainprediction and encoding, and compression efficiency of P frame is muchhigher than that of the I frame.

In the foregoing, the reference frame determined by reference framejudging module 14 b may be utilized as a reference in subsequent videoframe encoding performed by video encoding module 12 b, so as to executeinter-frame encoding. Meanwhile, the reference frame may be areconstructed frame obtained at video encoding end 10 b according to thevideo frame information fed back. As is well known by persons havingordinary skill in the art, the reconstructed frame refers to a videoframe formed after performing video encoding on an original video image,e.g., an original frame, captured by video capture module 11 b, in whichthe video frame is a video frame with loss compared with the originalframe.

Encoding mode of above reference frame may be I frame, or P frame. Thereference frame may be obtained from buffer of video encoding end 10 baccording to the video frame information fed back by feedback module 24b, in duration between reference frame judging module 14 b has completedthe encoding according to a previous frame and starts to encode currentvideo frame.

Encoding technologies of video encoding module 12 b may be determinedaccording to specific application. Video encoding technologies, such asAudio Video Interleaved (AVI), Moving Picture Experts Group (MPEG),DivX, Real Video, Windows Media Video, Audio Video Coding Standard (AVS)or/and H.264 may be adopted. Decoding technologies of video decodingmodule 22 b correspond to encoding technologies of video encoding module12 b. No further descriptions are provided here.

Video frame information fed back by feedback module 24 b includes atleast one of the follows. Information indicating whether decoding issuccessful, frame-loss information, video frame number informationbuffered, reference frame number, frame number information about thelast frame buffered in video decoding end 20 b.

Data transmitting module 13 b and data receiving module 12 b may benetwork transmission functional interfaces or functional modules ofdifferent user terminals. The user terminal may be computer, handheldelectronic device, communication device, video monitoring device, etc.Furthermore, the user terminal may be a client run in above devices,such as an Instant Messaging (IM) end, a video communication client. Thenetwork transmission functional interface or functional module of theuser terminal may be determined according to character of network 30 b.Network 30 b may also adopt a wired-based network, such as Internetwired network, digital television network. Network 30 b may also adopt awireless-based network, such as General Packet Radio Service (GPRS),Code Division Multiple Access (CDMA), Time Division Switching-CDMA(TDS-CDMA), Wireless Fidelity (WiFi), or a wireless network based onIEEE 802.11x series.

In the foregoing, detailed descriptions about the system provided by anembodiment of the invention were provided. Preferably, embodiments ofthe present invention also provide a video encoding communication deviceon the basis of feedback reference frame correspondingly. With referenceto FIG. 2 c, FIG. 2 c is a diagram illustrating structure of a videoencoding communication device on the basis of feedback reference frameprovided by an embodiment of the invention. As shown in FIG. 2 c, thedevice at least includes a video capture module 11 c configured tocapture current video image, a video encoding module 12 c configured toencode current video image, and a data transmitting module 13 cconfigured to transmit a video frame formed after encoding by videoencoding module 12 c to video decoding end through the network.Preferably, the device further includes the follows.

A reference frame judging module 14 c, which is located between videocapture module 11 c and video encoding module 12 c, is configured toobtain video frame information fed back by video decoding end, determinea reference frame used to encode current video image according to thevideo frame information, and provide the determined reference frame,which is used to perform encoding operations on current video image, tovideo encoding module 12 c.

Preferably, in the embodiment of the invention, there may be multipleimplementation modes for reference frame judging module 14 c. As shownin FIG. 2 c, reference frame judging module 14 c includes the follows.

A first judging unit 11 d, configured to judge whether the video frameinformation fed back by video decoding end includes frame-lossinformation and video frame number information.

A first determining unit 12 d, when judging result of first judging unit11 d is yes, configured to determine a reference frame which is used toencode current video image.

When judging result of first judging unit 11 d is no, video encodingmodule 12 c encodes current video image according to a predeterminedencoding method. The predetermined encoding method refers to encoding anI frame every 20 frames, and encoding a P frame every 5 frames with thelatest I frame as a reference frame.

Preferably, as shown in FIG. 2 d, reference frame judging module 14 cfurther includes the follows.

A second judging unit 13 d, which is located between first judging unit11 d and first determining unit 12 d, when judging result of firstjudging unit is yes, configured to judge whether there is a video framecorresponding to the video frame number.

When judging result of second judging unit 13 d is yes, firstdetermining unit 12 d is configured to take the video framecorresponding to the video frame number as a reference frame,

Thus, when judging result of second judging unit 13 d is no, videoencoding module 12 c may encode current video image to form a videoframe in the manner of I frame.

Until now, descriptions about structure of a video encodingcommunication device on the basis of feedback reference frame areprovided.

Preferably, embodiments of the invention also provide a video decodingcommunication device on the basis of feedback reference framecorrespondingly. As shown in FIG. 2 e, the device at least includes avideo decoding module 22 e configured to decode received video frames.The key is that the device further includes the follows.

Feedback module 24 e, which is connected with video decoding module 22e, is configured to feed back video frame information to video encodingend through the network according to decoding result of video decodingmodule.

The decoding result includes decoding success and decoding failure.

When decoding result is decoding failure, feedback module 24 e isconfigured to feed back video frame information to video encoding endthrough the network. When the video frame with failed decoding is abackbone frame, the video frame information carries frame numberinformation about the last frame buffered currently.

When implementing specifically, the device further includes the follows.

A data receiving module 21 e, which is connected with video decodingmodule 22 e, is configured to receive video frame data transmitted byvideo encoding end, package the video frame data to form a video frameagain, and provide the video frame to video decoding module 22 e.

Video playing module 23 e, configured to play video image decodedsuccessfully, when decoding result of video decoding module 22 e isdecoding success.

Until now, descriptions about structure of a video decodingcommunication device on the basis of feedback reference frame areprovided.

To make embodiments of the invention more clear, descriptions about flowprovided by embodiments of the invention are given.

With reference to FIG. 3, FIG. 3 is a diagram illustrating a basic flowon the basis of FIG. 2 a or FIG. 2 b in accordance with embodiments ofthe invention. As shown in FIG. 3, the flow may include the followingsteps.

Step S110, video encoding end receives video frame information fed backby video decoding end, determines a reference frame used to encodecurrent video image according to the video frame information, encodescurrent video image according to the determined reference frame, andsends out a video frame formed after encoding.

Step S120, video decoding end decodes received video frames, and feedsback video frame information to the video encoding end through a networkaccording to decoding result.

It can be seen that, step S110 actually demonstrates operations aboutvideo encoding communication on the basis of feedback reference frameprovided by an embodiment of the invention, while step S120 demonstratesoperations about video decoding communication on the basis of feedbackreference frame provided by an embodiment of the invention. To make theembodiment clearer, descriptions about steps S110 and S120 arerespectively provided in the following.

With reference to FIG. 4, FIG. 4 is a diagram illustrating flow aboutvideo encoding communication on the basis of feedback reference frame inaccordance with an embodiment of the invention, which is the detaileddescription in step S110. Meanwhile, the flow may be on the basis ofstructure illustrated in FIG. 2 c. As shown in FIG. 4, the flow mayinclude the follows.

Step S210, video encoding end captures original frames of video image.

Step S220, video frame information fed back is obtained and judged.

Step S230, a reference frame is determined according to the video frameinformation fed back;

Step S240, a video frame is formed after encoding current original frameaccording to the reference frame;

Step S250, the video frame formed after encoding is buffered;

Step S260, encoded video frame is sent to video decoding end;

Step S270, whether it is necessary to finish video communication isdetermined, if the video communication is continued, block 210 will beexecuted; otherwise, the video communication will be finished.

The reference frame in step S230 may be utilized as a reference toexecute inter-frame encoding, when video encoding module 12 c performingsubsequent encoding for video frames. Meanwhile, the reference frame instep S230 may be a reconstructed frame obtained at the video encodingend according to the video frame information fed back. Specifically, areconstructed frame refers to a video frame formed after performingvideo encoding on an original video image, e.g., an original frame,captured by video capture module 11 c, in which the video frame carriesloss compared with the original frame.

Encoding mode of the reference frame may be I frame, or P frame. Thereference frame may be obtained from buffer of the video encoding endaccording to the video frame information fed back, in duration betweenreference frame judging module 14 c has completed the encoding accordingto a previous video frame and starts to encode current video frame.

Specifically, the video frame information includes at least one of thefollowing. Information indicating whether decoding is successful,frame-loss information, video frame number information buffered,reference frame number, frame number information about the last framebuffered in video decoding end.

The step of obtaining and judging video frame information fed back instep S220 includes the follows.

Step S221, whether the video frame information fed back includesframe-loss information and video frame number information is determined.If yes, step S230 will be executed. Otherwise, step S222 will beexecuted.

Step S222, the video frame is encoded according to a predeterminedencoding method. The predetermined encoding method refers to encoding anI frame every 20 frames, and encoding a P frame every 5 frames with thelatest I frame as a reference frame. According to requirements ofpractical application, the predetermined encoding method may refer to anencoding rule, which encodes an I frame every A frames, and encodes a Pframe every B frames with the latest I frame as a reference frame. A andB may be arbitrary numbers.

Step for determining the reference frame according to the video frameinformation fed back in step S230 may include the follows.

Step S231, whether there is a video frame corresponding to bufferedvideo frame number in a buffer of video encoding end, if yes, step S232will be executed; otherwise, step S233 will be executed.

Step S232, the video frame corresponding to the buffered video framenumber is taken as a reference frame;

Step S233, a video frame is formed by encoding current original frame inthe manner of I frame, and step S260 may be directly executed.

Step for buffering a video frame formed after encoding in step S250includes the follows.

Step S251, number of a video frame formed after encoding is judged.

Step S252, a video frame corresponding to the video frame number isbuffered according to a rule for buffering video frames.

The rule for buffering video frames refers to that, if number of a videoframe formed after encoding is multiple of a certain number, the videoframe will be buffered; otherwise, the video frame will not be buffered.The certain number above in the rule may be numbers, such as 2, 3, 5 and8. The above buffered video frame is stored in a buffer. The buffer mayaccommodate a predetermined number of this video frame, e.g., N videoframes. The predetermined number N may be defined according to actualrequirements, e.g., 5 reconstructed frames encoded, but not limited tothis size. Meanwhile, buffered space may be adjusted, e.g., a videoframe buffered earliest may be removed when the buffer is full.Specifically, according to principle of accommodating N video frames bythe buffer, a video frame buffered earliest may be removed from thevideo frames buffered currently, and then, N video frames may bebuffered, in which N is a predetermined number.

Until now, the flow about a video decoding communication method on thebasis of feedback reference frame provided by an embodiment of theinvention may be implemented.

With reference to FIG. 5, FIG. 5 is a diagram illustrating a flow aboutvideo decoding communication on the basis of feedback reference frame inaccordance with a third embodiment which is provided based on the firstembodiment of the invention. FIG. 5 illustrates the detaileddescriptions in step S120. The flow in FIG. 5 may be on the basis ofstructure shown in FIG. 2 e. As shown in FIG. 5, the flow may includethe following.

Step S310, video decoding end receives video frame data transmitted byvideo encoding end, and packages the video frame data to form a videoframe again. If the video frame data has been packaged successfully,step S320 will be executed; otherwise, decoding failed information willbe returned.

Step S320, the video frame with newly and successful package may bedecoded.

Step S330, whether decoding is successful may be judged, if the decodingis successful, step S360 will be executed; otherwise, step S340 will beexecuted.

Step S340, whether it is necessary to feed back video frame informationto video encoding end may be judged, if yes, step S350 will be executed;otherwise, step S310 will be executed.

Step S350, the video frame information is fed back to the video encodingend according to a predetermined feedback rule.

Step S360, the video frame with successful decoding may be played;during the process of playing the video frame with successful decoding,if it is necessary to finish the video communication, the flow will befinished and exited. Otherwise, step S310 will be returned.

The step for feeding back the video frame information to the videoencoding end according to a predetermined feedback rule in step S350 mayinclude the follows.

Step S351, whether decoded video frame has already been buffered in thevideo encoding end may be judged, if yes, step S352 will be executed;otherwise, step S353 will be executed.

When sending the video frame by the video encoding end, if the videoframe has also been buffered currently, an identifier indicating thevideo frame has been buffered currently will be made for this videoframe to be sent out. Thus, when step S351 being executed, whether thedecoded video frame has already been buffered in the video encoding endmay be directly judged according to whether the decoded video frame hasthe identifier. Of course, other operation modes may also be adopted inthe embodiment of the invention to facilitate the video decoding end tojudge whether the decoded video frame has already been buffered in thevideo encoding end, which is not specifically limited in the embodimentof the invention.

Step S352, the decoded video frame is stored in a buffer of videodecoding end 20, and then, step S353 will be executed.

Step S353, whether it is necessary to feed back video frame informationthrough a network may be judged according to a predetermined rule, ifyes, the video frame information will be fed back, otherwise, no videoframe information will be fed back.

Specifically, the predetermined rule refers to all the decodingsuccessful information will not be fed back, that is, only when thedecoding is failed, video frame information will be fed back in theembodiment, Failed decoding is specifically as follows. For example,video frames with continuous frame numbers are not obtained in apredetermined duration, which is not limited here.

The video frame information fed back includes one of the follows.Successful information, frame-loss information, video frame numberinformation buffered, reference frame number, frame number informationabout the last frame in the buffer of the video decoding end. When theframe number information about the last frame is included, it means thatthe video frame with unsuccessful decoding is a backbone frame. Here,the backbone frame refers to a video frame, when decoding of the videoframe is failed, all of the subsequent frames except for the I framecannot be decoded correctly. That is, the backbone frame refers to avideo frame, which may be decoded separately independent of severalproximate video frames in front of it. The several proximate videoframes may be one frame proximate with the backbone frame, or may bemultiple frames proximate with the backbone frame.

The technical scheme provided by embodiments of the invention may beapplied in video communication service technologies with feedbackchannels, e.g., network video playing, video chatting, video conference,video monitoring and Video On Demand (VOD).

The foregoing is only preferred embodiments of the invention, which isnot used to limit the scope of the invention. Any equivalent structuresubstitution or flow substitution made utilizing contents of thespecification and attached figures in the invention, or applied directlyor indirectly in other related technical fields, should be covered bythe protection scope of the invention similarly.

1. A video communication method on the basis of feedback referenceframe, which is applied in a system comprising a video encoding end anda video decoding end, the method comprising: receiving, by the videoencoding end, video frame information fed back by the video decodingend, determining a reference frame for encoding current video imageaccording to the video frame information, encoding the current videoimage according to determined reference frame, sending a video frameformed after the encoding; decoding, by the video decoding end, receivedvideo frame, and feeding back the video frame information to the videoencoding end through a network according to decoding result.
 2. Thevideo communication method on the basis of feedback reference frameaccording to claim 1, wherein determining the reference frame comprises:determining whether the video frame information fed back by the videodecoding end comprises frame-loss information and video frame numberinformation, if the video frame information fed back by the videodecoding end comprises the frame-loss information and the video framenumber information, determining the reference frame.
 3. The videocommunication method on the basis of feedback reference frame accordingto claim 2, wherein when determining the video frame information fedback by the video decoding end does not comprise the frame-lossinformation and the video frame number information, a predeterminedencoding method is provided to the video encoding end; and thepredetermined encoding method refers to encoding an Intra frame (Iframe) every 20 frames, and encoding an Inter frame (P frame) every 5frames with the latest I frame as the reference frame.
 4. The videocommunication method on the basis of feedback reference frame accordingto claim 2, wherein when determining the video frame information fedback by the video decoding end comprises the frame-loss information andthe video frame number information, determining the reference framecomprises: determining whether there is a video frame corresponding tothe video frame number currently, if there is a video framecorresponding to the video frame number currently, taking the videoframe corresponding to the video frame number as the reference frame;when determining there is no video frame corresponding to the videoframe number, encoding the current video image in the manner of I frameto form the video frame.
 5. The video communication method on the basisof feedback reference frame according to claim 1, wherein when the videoframe is formed after encoding the current video image, whether it isnecessary to buffer the video frame currently is determined according tothe video frame number, if yes, N video frames are buffered, in which Nis a predetermined number.
 6. The video communication method on thebasis of feedback reference frame according to claim 5, whereinbuffering N video frames comprises: when current buffer space is full,removing a video frame buffered earliest from video frames currentlybuffered according to a principle of accommodating N video frames by thebuffer space, in which N is a predetermined number, and buffering the Nvideo frames.
 7. The video communication method on the basis of feedbackreference frame according to claim 2, wherein the decoding resultcomprises decoding success and decoding failure; and when the decodingresult is decoding failure, feeding back, by the video decoding end, thevideo frame information to the video encoding end through the network.8. The video communication method on the basis of feedback referenceframe according to claim 7, wherein when the decoding result at thevideo decoding end is decoding failure and determining the receivedvideo frame is a backbone frame, the video frame number informationcomprised in the video frame information fed back comprises frame numberinformation about the last frame buffered in the video decoding end. 9.A video communication system on the basis of feedback reference frame,wherein the system comprises a video encoding end, a video decoding end,a network respectively connected with the video encoding end and thevideo decoding end, the video encoding end at least comprises a videocapture module adapted to capture current video image, a video encodingmodule adapted to encode the current video image, and a datatransmitting module adapted to send a video frame formed after encodingby the video encoding module to the video decoding end through thenetwork, the video decoding end at least comprises a video decodingmodule adapted to decode received video frame, the video encoding endfurther comprises a reference frame judging module, the video decodingend further comprises a feedback module; the reference frame judgingmodule is adapted to receive the video frame information fed back by thefeedback module, and determine a reference frame for encoding thecurrent video image according to the video frame information; the videoencoding module is adapted to encode the current video image accordingto the reference frame determined by the reference frame judging module;the feedback module, which is connected with the video decoding module,is adapted to feed back the video frame information to the videoencoding end through the network and according to decoding result of thevideo decoding module.
 10. The video communication system on the basisof feedback reference frame according to claim 9, wherein the referenceframe judging module is adapted to judge whether the video frameinformation fed back by the feedback module comprises frame-lossinformation and video frame number information, if the video frameinformation fed back by the feedback module comprises the frame-lossinformation and the video frame number information, determine thereference frame; when the reference frame judging module judging thevideo frame information fed back by the feedback module doesn't comprisethe frame-loss information and the video frame number information, thevideo encoding module is adapted to encode the current video image witha method, in which an Intra frame (I frame) is encoded every 20 frames,and an Inter frame (P frame) is encoded every 5 frames with the latest Iframe as the reference frame.
 11. The video communication system on thebasis of feedback reference frame according to claim 10, wherein whenjudging that the video frame information fed back by the feedback modulecomprises the frame-loss information and the video frame numberinformation, the reference frame judging module is further adapted tojudge whether there is a video frame corresponding to the video frameinformation, if there is a video frame corresponding to the video frameinformation, take the video frame corresponding to the video framenumber information as the reference frame; when the reference framejudging module judging that there is no video frame corresponding to thevideo frame number, the video encoding module is further adapted toencode the current video image in the manner of I frame to form thevideo frame.
 12. The video communication system on the basis of feedbackreference frame according to claim 9, wherein the decoding resultcomprises decoding success and decoding failure; when the decodingresult of the video decoding module is decoding failure, the feedbackmodule is adapted to feed back the video frame information to thereference frame judging module through the network.
 13. The videocommunication system on the basis of feedback reference frame accordingto claim 12, wherein the video decoding end further comprises: a datareceiving module, which is connected with the video decoding end,adapted to receive the video frame sent by the video encoding end, andsend the received video frame to the video decoding module; and a videoplaying module, when the decoding result of the video decoding module isdecoding success, adapted to play the video image decoded successfully.14. A video encoding communication device on the basis of feedbackreference frame, which at least comprises a video capture module adaptedto capture current video image, a video encoding module adapted toencode the current video image, and a data transmitting module adaptedto transmit a video frame formed after encoding by the video encodingmodule to a video decoding end through a network, the device furthercomprises: a reference frame judging module, which is located betweenthe video capture module and the video encoding module, adapted toobtain video frame information fed back by the video decoding end,determine a reference frame used to encode the current video imageaccording to the video frame information, and provide determinedreference frame to the video encoding module which is adapted to executeencoding operations for the current video image.
 15. The video encodingcommunication device on the basis of feedback reference frame accordingto claim 14, wherein the reference frame judging module comprises: afirst judging unit, adapted to judge whether the video frame informationfed back by the video decoding end comprises frame-loss information andvideo frame number information; a first determining unit, when the firstjudging unit judging the video frame information fed back by the videodecoding end comprises the frame-loss information and the video framenumber information, adapted to determine the reference frame used toencode the current video image; the video encoding module, when thefirst judging unit judging the video frame information fed back by thevideo decoding end does not comprise the frame-loss information and thevideo frame number information, adapted to encode the current videoimage according to a predetermined encoding method, in which thepredetermined encoding method refers to encoding an Intra frame (Iframe) every 20 frames, and encoding an Inter frame (P frame) every 5frames with the latest I frame as the reference frame.
 16. The videoencoding communication device on the basis of feedback reference frameaccording to claim 15, wherein the reference frame judging modulefurther comprises: a second judging unit, which is located between thefirst judging unit and the first determining unit, when the firstjudging unit judging the video frame information fed back by the videodecoding end comprises the frame-loss information and the video framenumber information, adapted to judge whether there is a video framecorresponding to the video frame number currently; when the secondjudging unit judging there is a video frame corresponding to the videoframe number currently, the first determining unit is adapted to takethe video frame corresponding to the video frame number as the referenceframe; when the second judging unit judging there is no video framecorresponding to the video frame number currently, the video encodingmodule is adapted to encode the current video image in the manner of Iframe to form the video frame.
 17. A video decoding end device on thebasis of feedback reference frame, wherein the device at least comprisesa video decoding module adapted to decode received video frame, thedevice further comprises: a feedback module, which is connected with thevideo decoding module, adapted to feed back video frame information to avideo encoding end through a network and according to decoding result ofthe video decoding module.
 18. The video decoding end device on thebasis of feedback reference frame according to claim 17, wherein thedecoding result comprises decoding success and decoding failure; whenthe decoding result is decoding failure, the feedback module is adaptedto feed back the video frame information to the video encoding endthrough the network, when a video frame with failed decoding is abackbone frame, the video frame information carries frame numberinformation about the last frame in a current buffer.
 19. The videodecoding end device on the basis of feedback reference frame accordingto claim 18, wherein the device further comprises: a data receivingmodule, which is connected with the video decoding module, is adapted toreceive video frame data transmitted by the video encoding end, packagethe video frame data to form the video frame once again, and provide thevideo frame to the video decoding module; and a video playing module,when the decoding result of the video decoding module is decodingsuccess, adapted to play the video image with successful decoding.